Amsterdam - A landmark ruling to be given by a court in The Hague on Friday, on whether or not Senegal is obliged to try or extradite Chad's former leader, has major implications for other autocrats now in exile or considering exile to escape popular uprisings at home.
At one level, Friday's ruling will be the latest step in a long-running campaign by human rights activists to bring to trial Hissene Habre, who as Chadian president led a government they accuse of killing and torturing its opponents in the 1980s.
But legal experts say the case - brought by Belgium against Senegal, where Habre is living - could create a clear legal obligation on the states that harbour deposed despots to put them on trial or extradite them for trial elsewhere.
The ruling could worry former rulers like Zine al-Abidine Ben Ali, the Tunisian president overthrown in January 2011 at the start of the Arab Spring and now in exile in Saudi Arabia.
But it could also deter other leaders facing mounting violence at home, such as Syrian President Bashar al-Assad, from going into exile despite promises or guarantees of amnesty.
"If Belgium is successful, it will mean that third states would be able to oblige states on whose territory an accused war criminal resides to either prosecute such persons or extradite them to a state which can and wishes to prosecute," Malcolm Shaw, a law professor at Cambridge University, said in an email.
The case is reminiscent of Augusto Pinochet's arrest in London on a Spanish arrest warrant in 1998 for crimes committed while he was leader of Chile in the 1970s and 1980s.
Like that one, Belgium's case against Senegal highlights the creativity of human rights activists in seeking new ways to bring to trial leaders accused of serious crimes even when they are thought to be safe from justice.
"This case shows the tenacity and perseverance of a group of people who never gave up," said Reed Brody, the Human Rights Watch lawyer who worked with a group of victims to ensure Habre faced trial.
"There were five or six times when this case was dead."
Habre's eight-year rule over his oil-rich yet dirt-poor central African state, until ousted in a 1990 coup, became infamous for practices such as "arbatachar", where a prisoner is choked to death by having his wrists tied to his ankles from behind.
A 1992 truth commission in Chad accused him of being responsible for the killing of 40,000 people.
Senegal promised in 2000 to try Habre, who has been living in exile in the Senegalese capital Dakar, but after more than a decade of wrangling, it has not yet done so.
Activists turned to Belgium, which at the time claimed the right to prosecute crimes against humanity committed anywhere in the world. Chad has said it supports putting Habre on trial in Belgium.
Five years later, Belgian prosecutors indicted Habre and requested his extradition for torture - illegal under the U.N. Convention against Torture - and for crimes against humanity.
Belgium sued Senegal at the International Court of Justice in 2009, saying the torture convention, which Senegal signed, meant it must either prosecute Habre itself or extradite him.
Founded in 1945, the ICJ is a United Nations court better known for adjudicating abstruse boundary disputes between states than for deciding the fate of alleged criminals.
"For us, Belgium is the most plausible solution for trying Habre," said Jacqueline Moudeina, a lawyer for Habre's victims.
If the court finds in Belgium's favour, it could have implications for former leaders everywhere.
"It could have implications for peace agreements," said Dapo Akande, a law lecturer at Oxford University.
The court could hand down a ruling that would make it impossible to offer the amnesty and safe exile that many are proposing to encourage Syria's Assad, accused of atrocities during his country's uprising, to step down, he said.
International lawyers see the ICJ as a conservative court, reluctant to hand down rulings with far-reaching political consequences - though there have been exceptions in the past.
But most feel Belgium's case, in particular under the torture convention, is strong.
"They have very little wiggle room under the torture convention," said Akande, though the ICJ could dismiss the case, saying Belgium's involvement is too indirect, and much would depend on the precise wording of the judgment.
Pressure resulting from the case has already pushed Senegal's new government to promise to try Habre. More than two decades after his overthrow, it seems certain that Habre, 70, will stand before a court, a prospect many Chadians welcome.
"Belgian justice has all the advantages of a quick trial of Hissene Habre," said Mondo Fatime, who was imprisoned and beaten for four years under Habre. "We're dying off one by one. Time is against us, and we're calling for justice."